You might consider extra weight a risk to your heart, your energy levels, or even your joints, but you may not know much about the role bodyweight plays in a less obvious risk: cancer. “In the last few years, the relationship between excess weight and cancer has really started to get out there into the public domain,” says Neil Iyengar, MD, an investigator with the Breast Cancer Research Foundation and an attending physician at Memorial Sloan Kettering Cancer Center in New York City. There’s been a realization, backed up by recent scientific discoveries, “that maintaining weight is important not just for cardiovascular health.”
In fact, being overweight or obese is linked to a higher risk of 13 different types of cancer, as identified in a 2016 review from a working group assembled by the International Agency for Research on Cancer. In the U.S. each year, about 28,000 new cancer diagnoses in men and 72,000 in women are due to overweight or obesity, according to the National Cancer Institute (NCI). More and more recent studies point to fat around the midsection as particularly problematic.
The relationship between bodyweight and cancer risk is not quite as simple as “lose weight, avoid cancer” (nor does everyone who carries a few extra pounds end up with a cancer diagnosis). Most of the research linking cancer to bodyweight doesn’t follow people who shed pounds but rather folks who never lost weight, so it’s tough for researchers to identify exactly what would happen to your risk of cancer if you slim down. “The best advice is first avoid further weight gain,” Graham Colditz, MD, deputy director of the Institute for Public Health at Washington University in St. Louis, told Health in a prior interview. But losing a few spare pounds certainly can’t hurt, either. “Weight loss will lower risk of diabetes, heart disease, and stroke as well as cancer, so there are many good reasons to get back into shape, balance the food we eat with sufficient exercise, and avoid more weight gain or get some pounds off,” Dr. Colditz said.
Here are the 13 cancers that have been linked to extra weight so far, plus why those excess pounds make a difference.